As my tyres are touching very frequently the rear wheel arches, I'm looking at a clean and cheap way to raise the rear suspension à little bit (1 or 2cm seems enough).
I saw that there is a way to pretention the springs by turning the base of these springs.
Does anybody know what kind of pin wrench is needed to do that, and where to find such one wrench , preferably on the net.

Thanks

Francis

C-spanners came in a wide range of sizes; some have a swinging head arrangement so can cover a limited range. You just need to know the diameter of the collar and the width of the slots, a decent tool supplier (or even Cromwell ) or even Ebay should turn soomething up.
I had adjustable AVOs on my Esprit and when I bought it they were wound up so far the damn car looked like a dragster - they had done a good job of corroding the threads even though they were only a couple of years old, mind you, so don't be surprised if nothing moves like you expect it to.